java-ee Getting started with java-ee

Remarks

Building my First JavaEE Application (Hello World)

Let's understand something. JavaEE consists of a number of specifications. When you install an Application Server (Payara for example), you install all of the specifications at once. For example there's a specification for an ORM called JPA (Java Persistence API), a specification to build Component Based Web Applications called JSF (Java Server Faces), a specification to build REST web services and clients called JAX-RS.

So as you might guess, there's not only one way to build a simple Hello World application in JavaEE.

Secondly, the JavaEE spec has a specific structure of folders that looks something like this (simplified):

/projectname/src/main/java
/projectname/src/main/resources
/projectname/src/main/resources/META-INF
/projectname/src/main/webapp
/projectname/src/main/webapp/WEB-INF
 

Inside the /projectname/src/main/java we put all the java classes that we need.

Inside the /projectname/src/main/webapp we put html files, css files, javascript files, etc.

Inside the /projectname/src/main/webapp/WEB-INF goes some optional configuration files, such as web.xml and beans.xml.

For simplicity we will use the NetBeans IDE (it's free) to build our first JavaEE Application. You can find it here. Choose the JavaEE version and install it.

Create new project

• Open NetBeans IDE
• Go to File > New Project > Maven > Web Application and click Next.
• Change project name to HelloJavaEE, then click Next and Finish.

Clean and build the project

• Go to Run > Clean and Build Project (HelloJavaEE).

Deploy the WAR file

• In a browser, go to http://localhost:4848 (follow instructions to install payara server).
• Go to Applications > Click Deploy, Click on Select File and choose your war file (HelloJavaEE-1.0-SNAPSHOT.war) under ../NetBeansProjects/HelloJavaEE/target .

Deploy the WAR file directly from Netbeans

• Install Payara (see next chapter).
• In Netbeans, go to the 'Services' tab (Window-> Services if you don't see it).
• Right-click on Servers and select 'Add Server...'
• Select 'GlassFish Server', give it a name and click next.
• Point to your local Payara installation, select 'Local Domain' and click next.
• Leave the domain location settings as they are (Domain: domain1, Host: localhost, DAS Port: 4848, HTTP Port: 8080).
• Go to the 'Projects' tab (Windows -> Projects).
• Right-click on your project and select 'Properties'.
• In the left hand pane, go to 'Run' and select the Server you just added.
• (Optional) Change the context path. If you set the context path to '/MyFirstApplication' the default URL will be 'http://localhost:8080/MyFirstApplication'.

View results

• In a browser, go to http://localhost:8080/HelloJavaEE-1.0-SNAPSHOT

Voila! That's your first app using JavaEE technology. You should now start creating other "Hello World" apps using different specifications like JPA, EJB, JAX-RS, JavaBatch, etc...

Installation

First of all, you cannot "install" Java EE. Java EE consists of a number of specifications. You can install implementations of those specifications however.

Depending on your needs, there are lots of possibilities. To install most (or all) of the specifications, you can choose a Java EE 7 compatible Application Server. Depending on your needs, you can choose between application servers that implement the web profile or application servers that implement the full profile. For a list of Java EE7 compatible application servers see Java EE Compatibility.

Installing Payara Server Full

Prerequisites

• JDK 1.7 or later installed. You can find the Oracle JDK's here.

Steps

• Download Payara Server Full.
• Unzip the Payara Server at some location on your computer. We will use C:\payara41 as INSTALL_DIR for Windows users and /payara41 for Linux/Mac users.

Starting / stopping Payara from the command prompt

• Windows: Open a command prompt and execute the following command to start/stop Payara:

  "C:\payara41\bin\asadmin" start-domain

  "C:\payara41\bin\asadmin" stop-domain

• Linux/Max: Open a terminal and execute the following command to start/stop Payara:

  /payara41/bin/asadmin start-domain

  /payara41/bin/asadmin stop-domain

Starting Payara from Netbeans

• Add the Payara server to Netbeans (see previous chapter)
• Go to the 'Services' tab (Windows -> Services).
• Expand the 'Servers' item.
• Right-click on the Payara server and select 'Start'.
• (Optional) Right-click on the Payara server and select 'View Domain Admin Console' to go to the console.

To check that you're running the Application Server, open a browser and go to http://localhost:4848 to see the Payara Server Console.

Voila! Now it's time to build your first application using JavaEE and deploy it to your server!

What is Java EE?

Java EE stands for Java Enterprise Edition. Java EE extends the Java SE (which stands for Java Standard Edition). Java EE is a set of technologies and related specifications that are oriented towards the development of large-scale enterprise applications. Java EE is developed in a community driven process. So far the following versions of Java EE have been released:

• J2EE 1.2 (December12, 1999)
• J2EE 1.3 (September 24, 2001)
• J2EE 1.4 (November 11, 2003)
• Java EE 5 (May 11, 2006)
• Java EE 6 (December 10, 2009)
• Java EE 7 (April 5, 2013)

And Java EE 8 is expected to be released on the first half of 2017.

A key concept of the Java EE is that every Java EE version is comprised by a set of specific technologies. These technologies address specific JSRs (Java Specification Requests). In order for a programmer to use these technologies he needs to download an implementation of the Java EE technology specifications. The Java Community provides a reference implementation for each technology but other Java EE compliant technologies are developed and can also be used. The community provides a set of tests, namely the Java Compatibility Kit (JCK) that can be used by the developers of a JSR implementation to check if it is compliant or not with the JSR. The following table gives an overview of the technologies that comprise Java EE 7 and the related JSR that define the specs.

Java EE 7 Technology	JSR
Java Platform, Enterprise Edition 7 (Java EE 7)	JSR 342
Java API for WebSocket	JSR 356
Java API for JSON Processing	JSR 353
Java Servlet 3.1	JSR 340
JavaServer Faces 2.2	JSR 344
Expression Language 3.0	JSR 341
JavaServer Pages 2.3	JSR 245
Standard Tag Library for JavaServer Pages (JSTL) 1.2	JSR 52
Batch Applications for the Java Platform	JSR 352
Concurrency Utilities for Java EE 1.0	JSR 236
Contexts and Dependency Injection for Java 1.1	JSR 346
Dependency Injection for Java 1.0	JSR 330
Bean Validation 1.1	JSR 349
Enterprise JavaBeans 3.2	JSR 345
Interceptors 1.2 (Maintenance Release)	JSR 318
Java EE Connector Architecture 1.7	JSR 322
Java Persistence 2.1	JSR 338
Common Annotations for the Java Platform 1.2	JSR 250
Java Message Service API 2.0	JSR 343
Java Transaction API (JTA) 1.2	JSR 907
JavaMail 1.5	JSR 919
Java API for RESTful Web Services (JAX-RS) 2.0	JSR 339
Implementing Enterprise Web Services 1.3	JSR 109
Java API for XML-Based Web Services (JAX-WS) 2.2	JSR 224
Web Services Metadata for the Java Platform	JSR 181
Java API for XML-Based RPC (JAX-RPC) 1.1 (Optional)	JSR 101
Java APIs for XML Messaging 1.3	JSR 67
Java API for XML Registries (JAXR) 1.0	JSR 93
Java Authentication Service Provider Interface for Containers 1.1	JSR 196
Java Authorization Contract for Containers 1.5	JSR 115
Java EE Application Deployment 1.2 (Optional)	JSR 88
J2EE Management 1.1	JSR 77
Debugging Support for Other Languages 1.0	JSR 45
Java Architecture for XML Binding (JAXB) 2.2	JSR 222
Java API for XML Processing (JAXP) 1.3	JSR 206
Java Database Connectivity 4.0	JSR 221
Java Management Extensions (JMX) 2.0	JSR 003
JavaBeans Activation Framework (JAF) 1.1	JSR 925
Streaming API for XML (StAX) 1.0	JSR 173